Question: how do you know if everyone can see the same colour?

Sarah Ashwood answered on 13 Nov 2014:

That is a very good question, as colour is very much based on one persons perception of what they are seeing. However there wouldn’t really be any way to know whether we all see things exactly same. I think with biological research looking into how our eyes respond to colour and other external factors you can have some idea of whether we all look at things in the same way. However whether everyone’s brains process those signals in the same way would also be a factor. We know about colour blindness where certain colours are seen differently, however that is generally how one person cannot see differences between different colours (whether that is one specific colour or generally all colours)